H
HAYK
To use a low cost low noise high Hfe bc550C/560C as pre-drivers, I float them with a bootstraped supply. The result compared to Wolverine 3EF with single pair outputs is higher impedance and lower distortion.
These are measured with 1Mohm source 20ua 1khz input vs 22ua for Wolverine.
The biases are adjusted for minimum distortion 0.068% vs 0.31%.


These are measured with 1Mohm source 20ua 1khz input vs 22ua for Wolverine.
The biases are adjusted for minimum distortion 0.068% vs 0.31%.


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H
HAYK
H
HAYK
I am trying to understand the noise character of bc850c. I see on Infineon DS the noise figure. The noise figure if I do remember is amount of noise the circuits adds to the input noise which is to be the noise of the source resistance. The graphs show at 10k ohms. The lowest noise added is when the transistor is biased 30-50uA. Is this reasonable or I am seeing wrong?